We have built a reliable and robust system that takes as input an astronomical image, and returns as output the pointing, scale, and orientation of that image (the astrometric calibration or WCS information). The system requires no first guess, and works with the information in the image pixels alone. The success rate is very high (~ 99.9 percent for shallow UV and optical imaging survey data), with essentially no false positives. We are using this system to generate consistent and standards-compliant meta-data for all digital and digitized astronomical imaging, no matter what its archival state, including imaging from plate repositories, individual scientific investigators, and amateurs. This is the first step in a program of making all of the world's heterogeneous astronomical data searchable and interoperable.